The principle of switching devices for switchgear cabinets is well known. They are used, for example, to act as main switches for equipment whose components are accommodated in such a switchgear cabinet. Thus, in addition to the switching device, e.g. as main switch, other electrical and electronic components such as safety switches, circuit breakers or programmable components may be provided in the switchgear cabinet.
Such a switchgear cabinet is usually disposed in the vicinity of a machine that is controlled by the electronic inner workings of the switchgear cabinet. In order to operate or more specifically start up the machine, the switching device must change from an off-state to an on-state. For this purpose, known switching devices have a handle, also known as an operating mechanism or more specifically a rotary operating mechanism, which can be moved at least between a first and a second position.
In order to ensure that no electrical operating accidents occur during operation of equipment using such a switching device or rather such a switchgear cabinet, safety functions are provided. Thus in the case of known switching devices, for example, locking bars are present which are actuated by the handle when the installation is switched on.
If the handle is moved from a second position to a first position, i.e. from an off-position to an on-position, the locking bar is simultaneously moved from a release position to a locking position. A locking position is to be understood as meaning a position in which the locking bar is in engagement with the switchgear cabinet door or a locking bar component connected to the switchgear cabinet door, so that with the locking bar in this locking position the switchgear cabinet door is locked against opening. In other words, once the installation has been switched on via the handle of the switching device, the switchgear cabinet door can no longer be opened. Therefore, while the installation is switched on it is ensured that it is impossible to access the interior of the switchgear cabinet with the handle of the switching device in the on-position.
The disadvantage of known switching devices is that locking bar protection of this kind may be undesirable depending on the requirements and installed equipment situation. This is the case, for example, if a large number of switching devices are installed in a switchgear cabinet which is used, for example, for a large scale installations. It can also be disadvantageous if access to the interior of the switchgear cabinet is necessary during machine maintenance even though the installation is in operation, i.e. the handle is “on” in the first position.
For both cases, in known switching devices, a separate design must be provided which has no such locking bar or rather no such locking device. This results in increased manufacturing complexity on the one hand and increased storage costs on the other. The production costs also increase, as having two different variants means producing smaller quantities of each variant. Another disadvantage is that the deployment flexibility of each switching device is limited to the respective variant.